Wrong trigger. We’re trying to show that having strong libel laws makes it impossible for public figures to have a good reputation. But (A) is a principle about what happens when there are NO libel laws. That doesn’t help us prove a conclusion about what happens when there ARE libel laws.

We’re trying to prove that strong laws against libel makes it impossible for public figures to have a good reputation. (B) allows us to establish that some public figures will have bad reputations. But whether some have bad reputations doesn’t help show that NO public figure can have a good reputation.

Leads to wrong conclusion. We’re trying to show that under strong libel laws, public figures can’t have a good reputation. (C) is designed to prove that certain statements shouldn’t be considered libelous. But whether something should be considered libelous has no bearing on whether someone can develop a good reputation.

We’re trying to show that under strong libel laws, public figures can’t have a good reputation. (D) is designed to prove that under certain conditions, people won’t make negative statements about public figures. But we already know from the premise that under strong libel laws people won’t say anything bad about public figures. What we want is something to connect the fact that people won’t say anything bad about public figures to how it’s impossible to have a good reputation.

(E) provides a bridge from the premise to the conclusion. Restated, (E) asserts that if it’s impossible for public figures to have bad reputations, then public figures cannot have good reputations. We know from a premise that under strong libel laws, people won’t say anything bad about public figures. This strongly suggests that under strong libel laws, public figures can’t have bad reputations. (E) would then allow us to conclude that public figures can’t have good reputations.